It is well known to produce fluid flow by various mechanical devices such as fans and pumps. It is also well known that fluid flow can be produced by causing temperature or pressure changes in a fluid as by heating a fluid or gas to cause circulation of the fluid or circulation of the vapors created by the heating process. Heating of air and water by the sun for example produces fluid flow in the atmosphere and bodies of water. Most systems for producing fluid flow require the application of external energy or power such as electricity, heat, animal power, or other energy sources. It is also known that fluids can be moved through a porous membrane by osmosis, which requires no external energy, and by reverse osmosis which requires the application of pressure.
It is also known that gases consist of large numbers of molecules that are in continuous random motion. As used herein, molecule designates that smallest particle of any gas, which with some gases consists of combined atoms or in other uncombined atoms. The continuous random motion of the molecules of gas results in many collisions of the molecules. These collisions occur quite frequently for a gas at atmospheric pressure, about 3.times.109 per sec for each molecule of air. Because of these collisions, the direction of motion of a gas molecule is constantly changing. The diffusion of a molecule from one point to another consists of many short, straight-line segments as collisions buffet them around in random directions. Diffusion is faster for light molecules than for heavy ones. The average distance traveled by a molecule between collisions is known as the "mean free path". The higher the density of a gas, the smaller the mean free path. This means that the more molecules there are in a given volume, the shorter the average distance traveled between collisions. The term "diffusion" refers to the spread of a substance throughout a space or throughout a second substance. For example, the molecules of a perfume diffuse through a room.
The rate at which a gas is able o escape through a tiny hole depends on the molecular mass of the gas. The process of escape is known as "effusion".
It is further known that lighter atoms or molecules of gas have a higher average speed than heavier molecules. Thus, it is known that atoms of a lighter gas are with a higher average speed will pass through a hole more rapidly than will molecules of a heavier gas. This phenomenon has been used to separate gases of different weights by passing such gases through porous barriers or membranes.
The continuous zigzag motion of particles in a colloidal suspension is known as "Brownian movement". The motion is caused by impact of the molecules of the liquid upon the colloidal particles. Similarly, the Brownian movement in gases involves constant motion of dust particles as a result of uneven bombardment by air molecules. This invention utilizes a Brownian type movement in fluids.
There are many uses for apparatus that cause fluid flow including heating and cooling systems, power generation systems, fluid transfer systems among others.
There is a need for a system for causing fluid flow that uses little or no external energy to thereby minimize the cost of producing the fluid flow.
There is also a need for systems for improving the efficiency of separating gases of various molecular weights.